2-Methyl-2-trimethylsilyl-l ,3-dithiane

Methoxytrimethylsilane, 123 Methyl acetoacetate, 92 Methyl bromoacetate, 107 Methyl 11-hydroxyundecanoate, 58 Methyl lithium, 27,28 Methyl 10-undecenoatc, 58 2-MethyM,3-dithiane, 81 (V f ,55)-Methyl-3-phenyldimethyl-silyl-3-phenylpropionic acid. 53-4 2-Methyl-3-Phenylprop-2-enal, 111 2-Methyl-2-trimethylsilyl-l,3-dithiane, 81 2-Methyl-l-(trimethylsilyloxy)cydo-hex-l-ene, 100,109 2-Methyl-l-trimethylsilyloxy-cyclo-hex-6-ene, 100... 

To a solution of 2-methyl-l,3-dithiane (34.1 mmol) in THF (150 ml), cooled to — 30 °C, was added n-BuLi (34.1 mmol, 1.5 m in hexane) dropwise (3-5 ml/min). The resulting solution was stirred at —30 to — 20 °C for 1.5 h, and then TMSC1 (37.1 mmol) was added dropwise. After 2.5 h at — 25 °C, water (15 ml) was added, then most of the THF was removed in vacuo. Water and pentane were added, the layers were separated, and the aqueous layer was extracted thoroughly with pentane. The combined organic layers were washed with water, aqueous KOH (10%) and water, and dried. Concentration and distillation gave 2-methyl-2-trimethylsilyl-l,3-dithiane (26.8 mmol, 78%), b.p. 102°C/9.5mmHg. 

A mixture of 2-methyl-2-trimethylsilyl-l,3-dithiane (121 mmol), mercury(n) chloride (266mmol), and mercury(n) oxide (181 mmol) in methanol (225 ml) and water (25 ml) was stirred vigorously and heated under reflux for 2 h. It was then cooled and filtered, and the precipitate was... 

The anions, generated in situ by desilylation of silylacetylenes, allylsilanes, propargylsilanes, a-silyloxetanones, bis(trimethylsilylmethyl) sulfides, and other silane derivatives,can undergo nucleophilic addition to ketones and aldehydes (eq 11). Al-(C,C-bis(trimethylsilyl)methyl) amido derivatives can add to aldehydes followed by Peterson alkenation to form acyl enamines. Treatment of 2-trimethylsilyl-l,3-dithianes can generate dithianyl anions, which are capable of carbocyclization via direct addition to carbonyl or Michael addition (eq 12). The fluoride-catalyzed Michael additions are more general than Lewis acid-catalyzed reactions and proceed well even for those compounds with enolizable protons and/or severe steric hindrance (eq 13). ... 

Stereoselective addition of a dithiane anion to chiral 2-methyl-3-trimethylsilyl-3-buterud combined with the stereoselective addition of a Grignard reagent to the chi a-alkoxy ketone affords a practical method for the construction of a,y-dimethyl-a,3-dihydroxy compounds, useful intermediates for the synthesis of erythronolides (Scheme 33). -Hydroxy cartmxylic esters were synthesized by the addition of ethyl l,3-dithiolanyl-2-carboxylate enolate to a chiral aldehyde, followed by desulfurization. ... 

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